The present invention relates to a locating pin assembly for use in precision applications, more particularly for use in applications that locate a manufactured part such as gauging or machining.
Certain applications require precision location of manufactured parts such as applications that use gauges, holding fixtures, workholding fixture dies, assembly fixtures, and test equipment. The manufactured parts may be made by conventional means well known in the manufacturing or machining arts such as, but not limited to, stamping, casting, molding, and extrusions. In a machining process, it is desirable to use a static locating pin assembly to locate holes in manufactured parts. In such a process, a static pin having a chamfered head and a shaft is permanently attached to a static pin housing. The housing has a flange that is then either press fit or lock-screwed into a mounting block for locating holes in a machining process. There is not a standard width flange used for dimensionally holding the manufactured part in such a process, therefore, a rest pad having a predefined width and a locating surface must be used in combination with the static pin to precisely locate the part. The static pin then operates to locate holes disposed within a manufactured part relative to one another. The manufactured part engages the static pin to locate the holes disposed within the manufactured part. The chamfered head is used to guide the manufactured part towards the shaft of the static pin. The tolerance of the holes capable of encircling the shaft is very narrow using such a static pin. The diameter of the hole on the part being checked must be larger than the diameter of the static pin to provide clearance between the hole and to allow the static pin to properly locate the hole. During manufacturing of the manufactured part, the clearance varies over time between the pin and each hole, thus, making it more difficult for the static pin to properly locate each hole.
Another application requiring precision location of manufactured parts is in the gauging process. In the gauging process, a tapered pin assembly is used to locate holes in manufactured parts. Each assembly is typically custom-made for a specific part to be gauged. The custom process involves boring a hole in a tapered pin assembly mounting block, permanently mounting a custom made tapered pin disposed within a custom-made housing to the hole in the tapered pin assembly mounting block, and providing a compression spring between the bottom of the housing and the tapered pin. The surfaces of the assembly must be ground and hardened to provide for an accurate and a durable locating device. The custom-made assembly must be remade each time because an interchangeable pin assembly that is interchangeable with standard commercial locating pins is not readily available.
It is desirable to provide a ground locating surface located at a standard height above the mounting block for dimensionally holding the manufactured part.
It is desirable to eliminate the need for a rest pad to be used in combination with a locating pin housing as a locating surface.
It is desirable to provide a locating pin assembly that may use standard commercial locating pins to be easily and removably mounted into a mounting block.
It is desirable to provide a locating pin assembly that may easily locate holes in manufactured parts regardless of the holes"" sizes.
The devices and assemblies of the present invention are premised upon the discovery of a unique locating pin assembly for locating manufactured parts used in a precision locating process.
In general, the interchangeable locating pin assembly has:
a) a locating pin housing having a body, the body having an interior portion, and a flange for locating the manufactured part;
b) a locating pin having a tapered head for engaging the manufactured part at a single contact point, and a shank complementary in shape to the interior portion of the housing body for slidably engaging the interior portion of the housing body, the shank disposed in axial alignment with the tapered head extending axially downwardly from the tapered head;
c) means for axially moving the locating pin relative to the housing between a first extended position, a second partially retracted position, and a third fully retracted position; and
d) means for preventing movement of the pin relative to the housing.
The present invention thereby meets the needs identified above by providing an improved locating pin assembly for locating manufactured parts. The assembly eliminates the need to custom-make a locating pin tailored to each part. Instead the assembly can be made using standard commercial locating pins that are complementary in shape to standard commercial locating pin housings for use in many manufactured part precision locating applications.